V70 wont start once warm

[Robimoo]

Hi, I have a '98 V70 2.4 Classic. It has been a very reliable car up to this week. When the car is cold it starts fine and will run without any real problem. The problem comes when the car has been left for a short while. The car will not start. If I get the car running from cold, stop it and then try to restart immediately, it will restart OK. It is when it is left for some minutes that it is a problem.

There is spark at the plugs, I can hear the fuel pump priming when I turn the key.

When I try to start the engine, sometimes the starter motor seems to cut after a short time, as if the ECU is cutting it early. Sometimes (rarely) the engine will cough into life, run badly and then cut again.

Any suggestions gratefully received.

I am new to the forum so there may be other threads about the same issue that I have not seen.

Thanks

[Robimoo]

One further thing. There is a similar thread that mentions Crankshaft sensor issues that are like mine. The thing is my Haynes Manual is not clear on where this is. In a diagram it shows a 'Camshaft sensor' on top of the bell housing, but I thought this would be the position for the Crankshaft sensor. I would have thought the 'Camshaft sensor would have been near the top of the engine near the camshaft , logical. This is where it was on my Wife's Ford Focus. Can someone please tell me where the Camshaft sensor is located and where the Crankshaft sensor is located on a Mk1 V70 2.4L petrol ?

Thanks

[Chris_Rogers]

The camshaft sensor is indeed on the camshaft, usually the exhaust at the air filter end.

Have you tried monitoring the battery voltage when it won't start?
The starter motor stopping sounds like a failing battery or poor battery terminals.

[mattytowel]

I've been having similar problems for a couple of months with my 1995 850 N/A, there's another thread which has other people's suggestions on it. I've already tried a different FPR (used Bosch one), to no avail, so put the original back on. I'm currently running Redex in the petrol to try and clean the injectors in case they are leaking or have other fault - I may use STP cleaner once this tank full is clear. I may also try the Bosch FPR again, in case it was a combination of faults. Some things would be easier to check if I knew how to check the FPR pressure safely.

My car seems to be improving, but I don't know if it's the warmer weather or something I've done.

If you want to borrow a different FPR to see if it makes a difference you can.

Matthew

[Robimoo]

Hi Chris,

thanks. I have tried two batteries, one newly charged. There is no problem with the cranking speed. The problem is very repeatable and the cranking sounds good every time even when it wont start.

I have now found the camshaft sensor. The Haynes manual is hopeless here, but at least I have identified the two sensors and am confident of what is what.

I may try the crankshaft sensor first as it is mentioned in another thread. It is also the cheaper of the two. I have found another thread that mentions that they are worth changing at over 100k as a precaution anyway.

I will let you know how I get on.

Cheers

[Robimoo]

Hi Matty,

Thanks for the offer of the loan of your FPR. Very kind. I see you are just up the road in Manchester.

I'm going to try the crankshaft sensor first. I will let you know how I get on. What were the symptoms you had exactly ?

Cheer

[960kg]

Originally Posted by Robimoo

I'm going to try the crankshaft sensor first.

Cheer

Only trying to save you money but what makes you suspect a Crankshaft sensor as this only tells the ECU where TDC is, so therefore in practice if it starts ok cold it will start ok when hot!

I would replace the Coolant Temperature Sensor first this governs fuel amounts depending on the temp. of the engine and is £36 from Volvo.

[Robimoo]

Originally Posted by 960kg

Only trying to save you money but what makes you suspect a Crankshaft sensor as this only tells the ECU where TDC is, so therefore in practice if it starts ok cold it will start ok when hot!

I would replace the ECT first this governs fuel amounts depending on the temp. of the engine and is £36 from Volvo.

Hi. Not sure what the ECT is, please give me more info. Is it the temperature sensor ?

I am trying the camshaft sensor because there was mention of it on another thread with the same symptoms and after seeing that I started to google the problem and it has come up as a common issue on other forums including Subaru, BMW, SAAB. The sensor is £46 and about 5 mins to change.

[mattytowel]

Originally Posted by Robimoo

I'm going to try the crankshaft sensor first. I will let you know how I get on. What were the symptoms you had exactly ?

Have a read in here, for where I'm up to.

http://www.volvoforums.org.uk/showthread.php?t=138245

[AllWideDrum]

Originally Posted by Robimoo

Hi, I have a '98 V70 2.4 Classic. It has been a very reliable car up to this week. When the car is cold it starts fine and will run without any real problem. The problem comes when the car has been left for a short while. The car will not start. If I get the car running from cold, stop it and then try to restart immediately, it will restart OK. It is when it is left for some minutes that it is a problem.

There is spark at the plugs, I can hear the fuel pump priming when I turn the key.

When I try to start the engine, sometimes the starter motor seems to cut after a short time, as if the ECU is cutting it early. Sometimes (rarely) the engine will cough into life, run badly and then cut again.

Any suggestions gratefully received.

I am new to the forum so there may be other threads about the same issue that I have not seen.

Thanks

You don't say if it's an auto. I have occasionally had a similar problem traced to a stretched gear selector cable not activating the Park position fully. Engine would spin but not fire. Just a thought.